strace 4.15 released

[James Cowgill]

Hi,

On 06/01/17 00:51, Dmitry V. Levin wrote:
> On Tue, Jan 03, 2017 at 06:02:44PM +0000, James Cowgill wrote:
>> On 20/12/16 00:36, Steve McIntyre wrote:
>>> On Tue, Dec 20, 2016 at 03:16:17AM +0300, Dmitry V. Levin wrote:
>>>> On Tue, Dec 20, 2016 at 12:50:29AM +0100, Nahim El Atmani wrote:
>>>>> On Mon, 19 Dec 2016 18:30:29 +0000, Steve McIntyre wrote:
>>>>>> I'm seeing test suite failures on mips[1], mipsel[2] and mips64el[3]
>>>>>> on Debian machines.
>>>>>>
>>>>>> The 32-bit builds are both showing issues with fault injection. I
>>>>>> can't follow what the code is meant to be doing here, so no
>>>>>> ideas on what's wrong. :-(
>>>>>
>>>>> As Dmitry said earlier:
>>>>>
>>>>> On Tue, 15 Nov 2016 15:43:59 +0300, Dmitry V. Levin wrote:
>>>>>> Well, the mips kernel does not implement substitution of syscall numbers
>>>>>
>>>>> So it looks like the test has failed to SKIP on this target.
>>>>
>>>> As I'm not 100% sure there is no kernel support for mips, I decided
>>>> not to skip the test on mips until somebody investigates.
>>>
>>> Ah, OK. James Cowgill is my friendly local mips expert - let's see
>>> what he thinks... :-)
>>
>> I've had a look and I think there is a kernel bug here - specifically
>> affecting 32-bit programs run on 64-bit kernels (like all the Debian
>> buildds and the porterbox are). An extra PTRACE_SYSCALL stop is
>> happening which confuses everything. I'll look some more tomorrow.
> 
> Indeed, it seems to be a kernel bug in scall64-o32.S and scall64-n32.S.
> 
> According to current arch/mips/kernel/scall64-o32.S:trace_a_syscall
> (the same applies to arch/mips/kernel/scall64-n32.S),
> 
> if the syscall number after the first syscall_trace_enter call is out
> of range, there is a jump to not_o32_scall which in turn jumps to
> arch/mips/kernel/scall64-64.S:handle_sys64 (or to handle_sysn32 which
> then jumps on to handle_sys64).
> 
> Handle_sys64, unsurprisingly, does all over again, starting with
> a syscall_trace_enter call, which appears to be the second one
> and causes that extra syscall stop you observe with 32-bit tracees
> running on 64-bit kernels.

Just going through all the MIPS testsuite bugs again:

fault_injection*
The kernel bug above (no patch yet).

readahead
glibc bug fixed in 2.25
https://sourceware.org/bugzilla/show_bug.cgi?id=21026

pwritev
I debugged this to an Octeon specific kernel bug in Octeon's optimized
copy_from_memory implementation :S I've sent a patch to the linux-mips
list to fix this.
https://www.linux-mips.org/archives/linux-mips/2017-01/msg00094.html

newfstatat
Firstly we need to define TEST_BOGUS_STRUCT_STAT somewhere otherwise the
test just segfaults in glibc.

After that it suffers from the negative dates problem which happens when
glibc copies struct stat on mips n64. I thought I fixed this - did
something change?

Thanks,
James